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Thread: Help! I am running out of ides

  1. #1
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    Default Help! I am running out of ides

    Hi i have this project for class in which i have to ask the user to input a file name add 5 lines to it close the file open it again and add anothr 5 lines, then post everything to the screen here is my code

     
    import java.io.*;
    import java.util.*;
     
    public class siasJorge_project_03
    {
         public static void main(String[] args)
         {
    		 PrintWriter outputStream=null;
    		 Scanner keyboard = new Scanner(System.in);
    		 String line = " ";
     
    		 int input = 0;
             int input2 = 0;
     
             String name = " ";
     
             System.out.println("Please enter the name of the file we will be working on, dont forget to add the extensiuon type...\n");
             name = keyboard.next();
     
             try
    		       {
    		         BufferedReader inputStream = new BufferedReader(new FileReader(name));
    		         System.out.println("Please enter 5 lines of text: ");
    				 	for (input=0; input<5; input++)
    				    	{
    				          line = keyboard.nextLine();
    				          outputStream.println(line);
    				        }
     
    		         inputStream.close();
     
    	  	         outputStream = new PrintWriter(new FileOutputStream(name, true));
    				 System.out.println("Please enter 5 more lines of text: ");
    				 	for (input2 = 0; input2 < 5; input2++)
    	 			    	{
    	 			          line = keyboard.nextLine();
    	 			          outputStream.println(line);
    	 			        }
     
    		         inputStream.close();
     
    				 line = inputStream.readLine();
    				 while (line != null)
    		          {
    	                System.out.println("The content of " + name + " is : " + line);
    		            line = inputStream.readLine();
              		  }
              		}
     
    		       catch (FileNotFoundException e)
    		       {
    		         System.out.println("File " + name + " was not found");
    		         System.out.println(" or could not be opened. ");
    		       }
    		       catch (IOException e)
    		       {
    		         System.out.println("Error reading from file " + name);
         		   }
    		}
    }

    The code compiles but crashes giving me a Exception in thread "main" java.lang.NullPointerException at sisJorge_project_03.main<siasJorge_project_03.java :27>

    any clue what i am doing wrong??

    ThankYou


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Help! I am running out of ides

    java.lang.NullPointerException
    at sisJorge_project_03.main<siasJorge_project_03.java :27>
    Look at line 27 and find the variable that has a null value. Then backtrack in the code to find out why that variable does not have a valid value.
    If you don't understand my answer, don't ignore it, ask a question.

  3. #3
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    Default Re: Help! I am running out of ides

    would that be for the line = keyboard.nextLine(); ??

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: Help! I am running out of ides

    Can you look in your editor and count the lines?
    Or add a println that prints out the value of all the variables on the line and see if any of them are null.
    If you don't understand my answer, don't ignore it, ask a question.

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